Located over 1 billion light-years away from Earth, the combined galaxies have been named IRAS 14348-1447, partially after its discoverer, the Infrared Astronomical Satellite (IRAS), NASA said in a statement.

"It is one of the most gas-rich examples known of an ultraluminous infrared galaxy, a class of cosmic objects that shine characteristically — and incredibly — brightly in the infrared part of the spectrum," it said.

"Almost 95 per cent of the energy emitted by IRAS 14348-1447 is in the far-infrared!"

The space agency said the huge amount of molecular gas within IRAS 14348-1447, which fuels its emission, "undergoes a number of dynamical processes as it interacts and moves around".

It is responsible for its whirling and "ethereal appearance", which create "prominent tails and wisps extending away from the main body of the galaxy", NASA said.